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At least 217 records · Page 12

Experimenter's laboratory for visualized interactive science

The science activities of the 1990's will require the analysis of complex phenomena and large diverse sets of data. In order to meet these needs, we must take advantage of advanced user interaction techniques: modern user interface tools; visualization capabilities; affordable, high performance graphics workstations; and interoperatable data standards and translator. To meet these needs, we propose to adopt and upgrade several existing tools and systems to create an experimenter's laboratory for visualized interactive science. Intuitive human-computer interaction techniques have already been developed and demonstrated at the University of Colorado. A Transportable Applications Executive (TAE+), developed at GSFC, is a powerful user interface tool for general purpose applications. A 3D visualization package developed by NCAR provides both color-shaded surface displays and volumetric rendering in either index or true color. The Network Common Data Form (NetCDF) data access library developed by Unidata supports creation, access and sharing of scientific data in a form that is self-describing and network transparent. The combination and enhancement of these packages constitutes a powerful experimenter's laboratory capable of meeting key science needs of the 1990's. This proposal encompasses the work required to build and demonstrate this capability.

Hansen, Elaine R.↗

Automatic N(h,t) profiles of the ionosphere with a digital ionosonde

A method is described to accomplish automatic data selection and profile inversion to obtain ionospheric electron density profiles from digitized radio soundings. The profile inversion is based on a well-established formulation by which the optimum radio frequency sounding intervals can be specified from an approximate knowledge of the profile; the expected virtual height coordinates (h) at these frequencies (f) are estimated, and procedures are then used to select h(f) observations nearest the predicted coordinates from a subsequent digital ionogram. From these the next profile is obtained. The process adaptively follows the changing shape and detail of the profile. The procedure requires an average of 15 sec per profile on a standard data processing computer, and can be adapted, with benefit to online real-time use in a digital ionosonde.

Wright, J. W.↗

Standardization of the Definitions of Vertical Resolution and Uncertainty in the NDACC-archived Ozone and Temperature Lidar Measurements

The international Network for the Detection of Atmospheric Composition Change (NDACC) is a global network of high-quality, remote-sensing research stations for observing and understanding the physical and chemical state of the Earth atmosphere. As part of NDACC, over 20 ground-based lidar instruments are dedicated to the long-term monitoring of atmospheric composition and to the validation of space-borne measurements of the atmosphere from environmental satellites such as Aura and ENVISAT. One caveat of large networks such as NDACC is the difficulty to archive measurement and analysis information consistently from one research group (or instrument) to another [1][2][3]. Yet the need for consistent definitions has strengthened as datasets of various origin (e.g., satellite and ground-based) are increasingly used for intercomparisons, validation, and ingested together in global assimilation systems.In the framework of the 2010 Call for Proposals by the International Space Science Institute (ISSI) located in Bern, Switzerland, a Team of lidar experts was created to address existing issues in three critical aspects of the NDACC lidar ozone and temperature data retrievals: signal filtering and the vertical filtering of the retrieved profiles, the quantification and propagation of the uncertainties, and the consistent definition and reporting of filtering and uncertainties in the NDACC- archived products. Additional experts from the satellite and global data standards communities complement the team to help address issues specific to the latter aspect.

Detection of Atmospheric Composition Change (NDACC↗

Three years of observations from the International Space Station (ISS) by the Stratospheric Aerosol and Gas Experiment III (SAGE III/ISS)

After completion of the robot installation on the International Space Station (ISS) in early March 2017 as an external hosted science payload, the Stratospheric Aerosol and Gas Experiment (SAGE) III became the newest member to the family of space-based solar occultation instruments operated by NASA to investigate the Earth’s upper atmosphere since the late 1970s. One of three identical instruments, the SAGE III/ISS mission was revived in the early 2010s with a primary objective to monitor the vertical distribution of aerosol, ozone and other trace gases to enhance understanding of ozone recovery and climate change processes in the upper atmosphere. Presented here is the mission architecture, its implementation, and data produced by SAGE III/ISS, including their precision and coverage. The 51.6-degree inclined orbit of the ISS is well-suited for solar occultation and provides near-global observations on a monthly basis with coverage of low and mid-latitudes similar to that of the SAGE II mission, which operated over two decades. The nominal science products, derived from sampling spectra covering 290nm to 1030nm and a photo-diode near 1550 nm, include high resolution vertical profiles of ozone, nitrogen dioxide and water vapor, along with multi-wavelength aerosol extinction. Although in the visible portion of the spectrum the brightness of the Sun is a million times that of the full Moon, the SAGE III instrument design covers this large dynamic range, performing lunar occultations on a routine basis to augment the solar products. The standard lunar products include ozone and nitrogen trioxide. Routine observations began June 2017 and continue to the present. This has enabled observations of significant perturbations of the stratosphere induced by three different wildfire events (two of which were record setting), four volcanic eruptions and two changes of the Quasi-Biennial Oscillation (QBO) phase, as represented in the standard data products.

ozone↗

Exchange of Standardized Flight Dynamics Data

Spacecraft operations require the knowledge of the vehicle trajectory and attitude and also that of other spacecraft or natural bodies. This knowledge is normally provided by the Flight Dynamics teams of the different space organizations and, as very often spacecraft operations involve more than one organization, this information needs to be exchanged between Agencies. This is why the Navigation Working Group within the CCSDS (Consultative Committee for Space Data Systems), has been instituted with the task of establishing standards for the exchange of Flight Dynamics data. This exchange encompasses trajectory data, attitude data, and tracking data. The Navigation Working Group includes regular members and observers representing the participating Space Agencies. Currently the group includes representatives from CNES, DLR, ESA, NASA and JAXA. This Working Group meets twice per year in order to devise standardized language, methods, and formats for the description and exchange of Navigation data. Early versions of some of these standards have been used to support mutual tracking of ESA and NASA interplanetary spacecraft, especially during the arrival of the 2003 missions to Mars. This paper provides a summary of the activities carried out by the group, briefly outlines the current and envisioned standards, describes the tests and operational activities that have been performed using the standards, and lists and discusses the lessons learned from these activities.

standards↗

QuikSCAT Mission

The QuikSCAT Mission of the National Aeronautics and Space Administration (NASA) is planned for launch in Spring 1999, reducing the data gap in ocean-wind vector created by the loss of the NASA Scatterometer (NSCAT) on the Japanese Advanced Earth Observing Satellite (ADEOS) spacecraft. The NSCAT instrument ceased functioning when ADEOS failed on June 30, 1997. The follow-on scatterometer for monitoring ocean winds, called SeaWinds, is scheduled for launch on the Japanese ADEOS-II spacecraft in 2000. The Jet Propulsion Laboratory (JPL) has met the challenge to develop and integrate the instrument, ground system, and launch vehicle in less than a year. QuikSCAT will use pencil-beam-antennas in a conical-scan design which is more compact than the fixed fan-beam design of NSCAT. The antenna will radiate ku-band microwaves at 40 and 46 incident angle and measure the backscatter power across a continuous 1800 km swath. QuikSCAT is capable of providing wind-speed and wind-direction at 25 km resolution over 92 percent of the Earth's ice-free oceans every day, under both clear and cloudy conditions. Standard data products will be delivered to science users within 14-days, and fast data products will be available to operational users within two hours of data acquisition. QuikSCAT will be managed by JPL for the NASA's Office of Earth Science Enterprise. It will be launched from Vandenberg Air Force Base, aboard a Titan II vehicle. The satellite core-systems was built by Ball Aerospace Systems Division, Boulder, CO. The operation of QuikSCAT is expected to overlap with ERS-2 and SeaWinds. Spaceborne scatterometers have demonstrated a broad spectrum of scientific applications, including weather systems, wind-driven ocean circulation, land vegetation, polar ice morphology and dynamics, and Ocean-atmosphere-ice interaction.

Liu, W. Timothy↗

Research and operational efforts in support of Skylab experiment M093

The objectives of Skylab Experiment M093 were to measure electrocardiographic signals during spaceflight, to elucidate the electrophysiological basis for the changes observed, and to assess the effect of the change on the human cardiovascular system. Vectorcardiographic methods were used to quantitate changes, standardize data collection, and to facilitate reduction and statistical analysis of data. In this report the authors describe the M093 experiment design, the data transmission system, data reduction methods, and the analysis of data from the three Skylab missions. The report also includes clinical applications of the techniques developed for Skylab Experiment M093.

Smith, R. F.↗

Compiling the space shuttle wind tunnel data base: An exercise in technical and managerial innovators

Engineers evaluating Space Shuttle flight data and performance results are using a massive data base of wind tunnel test data. A wind tunnel test data base of the magnitude attained is a major accomplishment. The Apollo program spawned an automated wind tunnel data analysis system called SADSAC developed by the Chrysler Space Division. An improved version of this system renamed DATAMAN was used by Chrysler to document analyzed wind tunnel data and data bank the test data in standardized formats. These analysis documents, associated computer graphics and standard formatted data were disseminated nationwide to the Shuttle technical community. These outputs became the basis for substantiating and certifying the flight worthiness of the Space Shuttle and for improving future designs. As an aid to future programs this paper documents the lessons learned in compiling the massive wind tunnel test data base for developing the Space Shuttle. In particular, innovative managerial and technical concepts evolved in the course of conceiving and developing this successful DATAMAN system and the methods and organization for applying the system are presented.

Kemp, N. D.↗

Aerodynamic Characteristics of NACA 16-Series Airfoils

Standard data from literature incorporated into program. Comprehensive and easily-accessible data bank of aerodynamic characteristics of NACA 16series airfoils incorporated into AIRFOIL program for use in propeller performance research. Low-drag, high-critical-speed airfoils effective in advanced turbo-prop designs currently under investigation. AIRFOIL written in FORTRAN IV for batch execution.

Maksymiuk, C. M.↗

Experimental and theoretical studies of time-averaged and time resolved rotor heat transfer

Efforts in support of the Space Shuttle Main Engine (SSME) structural durability program have concentrated on obtaining detailed time-averaged and time-resolved (or phase-locked) measurements on a full-scale rotating turbine both with and without cold gas injection and on theoretical studies designed to improve the prediction capability for these turbine flows. The experimental efforts have concentrated on use of the Garrett TFE 731-2 hp turbine. However, it has been possible to apply the theoretical efforts to predicting heat-flux distributions obtained for two additional turbines - i.e., (1) the Garrett low aspect ratio turbine (LART) and (2) the Teledyne 702 turbine. The experimental technique is the short duration, shock-tunnel approach, in which fast-response, thin-film resistance thermometers are used to measure surface temperature histories at prescribed locations on the turbine component parts. Heat-flux values are then inferred from the temperature histories by using standard data reduction procedures. The turbine being used is the Garrett TFE 731-2 hp stage, and both the nozzle guide vanes and the rotor blades are heavily instrumented with thin-film heat-flux gauges. Depending on how the data from a particular heat-flux gauge are recorded, one can get either time-resolved (or phase-locked) or time-averaged results. Both types of data are illustrated.

Dunn, M. G.↗

Methodology requirements for intelligent systems architecture

The methodology required for the development of the 'intelligent system architecture' of distributed computer systems which integrate standard data processing capabilities with symbolic processing to provide powerful and highly autonomous adaptive processing capabilities must encompass three elements: (1) a design knowledge capture system, (2) computer-aided engineering, and (3) verification and validation metrics and tests. Emphasis must be put on the earliest possible definition of system requirements and the realistic definition of allowable system uncertainties. Methodologies must also address human factor issues.

Grant, Terry↗

Recent trends in geographic information system research

This paper reviews recent contributions to the body of published research on Geographic Information Systems (GISs). Increased usages of GISs have placed a new demand upon the academic and research community and despite some lack of formalized definitions, categorizations, terminologies, and standard data structures, the community has risen to the challenge. Examinations of published GIS research, in particular on GIS data structures, reveal a healthy, active research community which is using a truly interdisciplinary approach. Future work will undoubtably lead to a clearer understanding of the problems of handling spatial data, while producing a new generation of highly sophisticated GISs.

Clarke, K. C.↗

Knowledge-based control of an adaptive interface

The analysis, development strategy, and preliminary design for an intelligent, adaptive interface is reported. The design philosophy couples knowledge-based system technology with standard human factors approaches to interface development for computer workstations. An expert system has been designed to drive the interface for application software. The intelligent interface will be linked to application packages, one at a time, that are planned for multiple-application workstations aboard Space Station Freedom. Current requirements call for most Space Station activities to be conducted at the workstation consoles. One set of activities will consist of standard data management services (DMS). DMS software includes text processing, spreadsheets, data base management, etc. Text processing was selected for the first intelligent interface prototype because text-processing software can be developed initially as fully functional but limited with a small set of commands. The program's complexity then can be increased incrementally. The intelligent interface includes the operator's behavior and three types of instructions to the underlying application software are included in the rule base. A conventional expert-system inference engine searches the data base for antecedents to rules and sends the consequents of fired rules as commands to the underlying software. Plans for putting the expert system on top of a second application, a database management system, will be carried out following behavioral research on the first application. The intelligent interface design is suitable for use with ground-based workstations now common in government, industrial, and educational organizations.

Lachman, Roy↗

Evolution of an Intelligent Information Fusion System

Consideration is given to the hardware and software needed to manage the enormous amount and complexity of data that the next generation of space-borne sensors will provide. An anthology is presented illustrating the evolution of artificial intelligence, science data processing, and management from the 1960s to the near future. Problems and limitations of technologies, data structures, data standards, and conceptual thinking are addressed. The development of an end-to-end Intelligent Information Fusion System that embodies knowledge of the user's domain-specific goals is proposed.

Campbell, William J.↗

Potential vorticity index

Using standard data analysis techniques, researchers explore the links between disturbance growth and quasi-geostrophic potential vorticity (PV) gradients; appearance and disappearance of cutoff lows and blocking highs and their relation to a zonal index (properly defined in terms of PV); and teleconnections between different flow patterns and their relation to the zonal index. It was found that the PV index and the eddy index correlate better than a zonal index (defined by zonal wind) and the eddy index. In the frequency domain there are three frequencies (.03, .07 and .17 cpd (cycle per day) corresponding to periods of 33, 14 and 6 days) at which PV index and the eddy index exhibit local maxima. The high correlation found at periods of 33 days is mainly due to eddy activity at high latitudes while the local correlation maxima found at the shorter periods are mainly due mid-latitude eddy activity. The correlation between the PV index and the geopotential height anomaly at 500 mb, at each grid point in the Northern Hemisphere, shows the existence of most of the teleconnection patterns summarized by Wallace and Gutzler (1981): the North Atlantic Oscillation, the North Pacific Oscillation, and the Pacific/North American patterns. Results show that the Isentropic Potential Vorticity (IPV) analysis can be a very useful and powerful tool when used to understand the dynamics of several large scale atmospheric systems. Although the data are limited to only one winter, and it is difficult to assess the statistical significance of the correlation coefficients presented here, the results are encouraging from physical viewpoint.

Barcilon, Albert↗

Heat-transfer and surface-pressure measurements for the SSME fuel-side turbopump turbine

Detailed heat flux and surface pressure distribution on the first-stage vane and blade of the Space Shuttle Main Engine fuel side turbopump turbine are examined. The specific turbine being utilized for the study is a combination of actual engine hardware and reproduced hardware consistent with that being used at NASA-Marshall for the initial measurements in their newly constructed blow-down turbine test facility. The facility is of the short duration shock tunnel variety, which permits use of thin film thermometers which are used to measure the surface temperature histories at prescribed locations on the turbine component parts. Heat flux values are then inferred from the temperature histories using standard data reduction procedures. The measurement program is described in detail.

Dunn, Michael G.↗

Characterization of slow and fast phase nystagmus

A current literature review of the analog and digital process of vestibular and optical kinetic nystagmus reveals little agreement in the methods used by various labs. The strategies for detection of saccade (fast phase velocity component of nystagmus) vary between labs, and most of the process have not been evaluated and validated with a standard database. A survey was made of major vestibular labs in the U.S. that perform computer analyses of vestibular and optokinetic reflexes to stimuli, and a baseline was established from which to standardize data acquisition and analysis programs. The concept of an Error Index was employed as the criterium for evaluating the performance of the vestibular analysis software programs. The performance criterium is based on the detection of saccades and is the average of the percentages of missed detections and false detections. Evaluation of the programs produced results for lateral gaze with saccadic amplitude of one, two, three, five, and ten degrees with various signal-to-noise ratios. In addition, results were obtained for sinusoidal pursuit of 0.05, 0.10, and 0.50 Hz with saccades from one to ten degrees at various signal-to-noise ratios. Selection of the best program was made from the performance in the lateral gaze with three degrees of saccadic amplitude and in the 0.10 Hz sinusoid with three degrees of saccadic amplitude.

Lessard, Charles S.↗

Guidance, navigation, and control subsystem equipment selection algorithm using expert system methods

Enhanced engineering tools can be obtained through the integration of expert system methodologies and existing design software. The application of these methodologies to the spacecraft design and cost model (SDCM) software provides an improved technique for the selection of hardware for unmanned spacecraft subsystem design. The knowledge engineering system (KES) expert system development tool was used to implement a smarter equipment section algorithm than that which is currently achievable through the use of a standard data base system. The guidance, navigation, and control subsystems of the SDCM software was chosen as the initial subsystem for implementation. The portions of the SDCM code which compute the selection criteria and constraints remain intact, and the expert system equipment selection algorithm is embedded within this existing code. The architecture of this new methodology is described and its implementation is reported. The project background and a brief overview of the expert system is described, and once the details of the design are characterized, an example of its implementation is demonstrated.

Allen, Cheryl L.↗